Installing 3 MV Robicon Perfect Harmony drives on the chillers of 10 air conditioning systems

Installing 3 MV Robicon Perfect Harmony drives on the chillers of 10 air conditioning systems

Energy efficiency and the measures we can take to make buildings environmentally friendly are becoming increasingly important in the United States. The more extreme the environmental conditions, the more difficult the challenge, because resort operators in the desert city of Las Vegas know this well. It is precisely this situation that requires MGM Bellagio to implement such sustainable solutions: While guests enjoy the pleasant cooling effect of the resort’s automatic air conditioning equipment, the advanced drive technology developed by Siemens is playing Function in the background to effectively control the coolers, pumps and fans of the cooler factory. As part of the modernization project, by installing variable speed drives, the resort has successfully cut its annual energy costs by 25% and saved US$400,000 in the past five years.

As President Obama recently announced, the United States will double its energy efficiency by 2030. Measures designed to achieve this goal will include construction, industry, transportation, and infrastructure, as these account for about 40% of US energy consumption. Five years ago, US resort hotel chain MGM Resorts International seized the opportunity to make profitable investments in energy-efficient buildings, and these investments are still working today.

As part of the investment plan, one of the many projects undertaken was the modernization of the chillers in the "Bellagio Resort and Casino" in Las Vegas, which Siemens implemented in 2008. The high-speed driver in the chiller can more effectively drive the chiller, water pump and fan, while providing the best automatic air conditioning, making guests feel more comfortable.

In 2013, five years after the project was completed, John Leslie, the energy manager of MGM, took stock of his stock: "When we made the decision to invest in the energy saving plan, we were fully aware When it comes to potential savings. I look at our energy usage trends in the past five years and I have to admit that we have exceeded our expectations. The return on investment was realized within 12 months. Compared with before, we were reduced by 25%. By 30% a year, we have saved more than 420,000 US dollars in electricity bills for our chillers."

From inefficient continuous cooling to efficient and comfortable air conditioning

Before the implementation of the transformation project with Siemens, Bellagio Resort had a total of 10 compressors generating 18,000 tons of cooling per month, and the monthly electricity cost was approximately US$570,000. In addition, even if the temperature in the building does not require a chiller, the chiller can still run at full power.

By installing three medium-voltage Robicon Perfect Harmony drives on the coolers of a total of ten air conditioning systems, Siemens made it possible to flexibly adapt the output to actual needs. This is because the variable speed drive only provides the electric motor with the power needed to meet the actual demand. When the cooling demand drops, the converter responds by reducing its output. In addition, Robicon Perfect Harmony drives include several low-voltage batteries, which are connected in series to form a medium-voltage system. Thanks to this topology, the converter can be accurately scaled to adapt to various voltages and output power levels, which has great advantages when it comes to various HVAC applications.

Maximum availability is essential

An equally important issue to be solved by this project is the availability of the air conditioning system. This is because hoteliers need to know that the hotel room will be reliably cooled, especially if the resort happens to be in the desert. Due to its modular structure and the fact that faulty batteries can be bypassed during inverter operation, Robicon Perfect Harmony drives have extremely high availability.

Completely independent of the redundant bypass control of the power unit, it can automatically bypass the faulty battery in 450 milliseconds (in other words, in less than half a second). The protection principle of endurance process ProToPS not only provides the response to the drive, but also enables the process to be tripped in response to faults, while ProToPS provides a hierarchical warning system. This control strategy provides the time required to assess the situation and respond appropriately to avoid system shutdown.

The advantages of Robicon Perfect Harmony drives are especially obvious when they are used in retrofit projects. Because it is compatible with existing motors-regardless of their age, brand or voltage and frequency requirements, the cost of replacing the entire Bellagio refrigerator factory can be avoided. Modified components can also be installed and commissioned quickly and cost-effectively.

Because unlike conventional converters consisting of up to five different components (such as harmonic filters, power factor correction, transformers, converters and output filters), the topology of Robicon Perfect Harmony drives only requires input transformers and converters. The integrated system can not only speed up, but also reduce installation and commissioning costs. When carrying out modernization work, it is therefore possible to minimize process downtime and provide greater flexibility in overall project management.

summary

If within the current environmental policy framework continue to promote energy efficiency in the United States, especially themes related to building technology, MGM Resorts International will be regarded as one of the pioneers who recognize the potential of high efficiency driving technology. Especially in extreme conditions, such as operating a resort in a desert city like Las Vegas, sustainable, well-planned solutions are required. By modernizing the chiller with Siemens variable speed drives, hoteliers not only succeeded in reducing their own energy consumption and cutting huge electricity bills, but also improving the comfort of guests by improving the control of the air-conditioning system.

Tom Shearer, Western Sales Manager, Siemens Industries, USA

Published on November 18, 2013